The present invention relates to a magnetic recording tape cartridge, and more particularly to an improvement of a magnetic recording tape cartridge having a pad device for giving pressure contact of the magnetic recording tape to the magnetic head of a tape recorder.
U.S. Pat. No. 3,529,788 discloses an example of a recording tape cartridge provided with a magnetic shielding plate and a pad device.
Detailed construction of essential portions of the conventional magnetic recording tape cartridge of the prior art as mentioned above is illustrated in FIG. 1 and FIG. 2, wherein a magnetic shielding plate 100 and a pad device 101 composed of a resilient plate 102 and a cubic cushioning pad 103 are disposed in parallel facing an opening 104 defined in front wall 109 of the cartridge 105 for receiving a magnetic head (not shown) of a tape recorder.
In a process of making a cartridge commercially, the magnetic shielding plate 100 is installed by mounting its bent ends 100a on a pair of base pieces 106 protruding from tape guiding pins 107 and the plate 100 is clamped by backward ends 108a of a pair of ribs 108 extending in a backward direction from the front wall 109 and a boss 110.
After installation of the plate 100, the pad device 101 is installed relative to said base pieces 106 by inserting both end portions of the resilient plate 102 within the gaps defined by the guide pins 107 and both bent ends 100a of the plate 100.
Under such a situation, during the process of installation of these elements, if the magnetic shielding plate 100 shifts upward even to a slight degree due to vibration or shock of intermittent movements of a conveyer by which the respective cartridges are transferred, a gap G between the base pieces 106 and the bent ends 100a of the magnetic shielding plate 100 is created as shown by the dot-dash lines A in FIG. 2 and the plate 102 of the pad device 101, which originally tends to be inclinded in a forward direction, falls into said gap G as shown by the dot-dash lines B with the result that the procedure of installation of these elements into the cartridges must be stopped.
The above mentioned magnetic shielding plate 100 which is inserted in the receiving groove formed on the lower case 111 with some play tends to move idly in both the forward or backward directions and in the lateral directions. Therefore, such lateral movement, i.e., leftward and rightward directions of the magnetic shielding plate 100, tends to cause such problems that the pad device 101 is displaced away from the guide pins 107, resulting in failure of exertion of the required contact pressure on the recording tape and the recording head.